"One should stress the fact that the electron beam consists of a large number of negatively charged electrons moving at a good fraction of the speed of light (about 0.25 c for a typical acceleration voltage of 17 kV)."

17 kV

The experimentation of creating a television system began in the late Nineteenth
Century. In 1884, a German scientist, Paul Nipkow proposed the first workable
television system. In 1900-1920 early versions of the picture tube started appearing.
Methods of amplifying electronic signals and the formulation of the electronic
scanning principle became the basis of modern television. A television is an electronic
system that produces images on a screen. This is currently done with a cathode-ray
tube, which contains an electron gun that must be operated at a high voltage.
The electron gun shoots a high-energy beam of electrons toward a phosphorescent
screen, creating a bright spot that appears where the beam hits the screen.

A full screen image is formed when the electron beam is deflected in the vertical
and horizontal directions either by magnetic fields or the electrostatic effect
of electrodes within the tube. The magnetic fields and the electrostatic effect
of electrodes within the tube are produced by coils found in the neck of the tube.

Some cathode-ray tubes use multiple beams of electrons, displaying more than
one color. These are made for television, oscilloscopes, computer terminals, automated
teller machines and radar displays.

The voltage of a television picture tube has increased gradually. In the 1940s
only 3000-6000 volts were needed for the final anode. Today, 25,000 volts are
typical as television has advanced from small black and white sets to larger color
screens.